1. Field of the Invention
Disclosed herein is a method of and equipment for preparing, for a continuous on-line analysis, an analysis sample that is formed from a sample material, which is taken from a material flow containing solid matter and liquid.
2. Description of Related Art
In industrial processes that treat and process slurries containing solid matter, there is often a need to regularly and continuously control the process on the basis of the element contents of the solid matter in the slurry. It is well-known to use certain analyzing methods in analyzing slurries that contain solid matter. These include optical analyzing methods, nuclear magnetic resonance, laser emission spectroscopy, and capture gamma spectroscopy as well as methods utilizing X-rays, such as the method based on X-ray fluorescence. In order to optimally observe and control the industrial processes on the basis of such measurement results, samples should be taken continuously from the process flow and immediately analyze them without a delay, which is significant compared with the time constant of the process. Mineral separation processes and processes of the hydrometallurgy field are examples of industrial processes, wherein a real-time analyzing of slurries and liquids are required. Flotation, magnetic and gravitational separation, extraction of metals, cleaning of liquid, as well as electrolytic cleaning and recovery processes represent mineral and hydrometallurgy processes that use real-time analyzers.
One technique commonly used in laboratories for analyzing slurry samples is to filter the slurry and dry and grind the solid matter into a finer form, and to compress the sample into a briquette for each analysis. The briquette thus obtained is further taken to an analyzer. However, as the intention is to analyze fine-grained, powdery samples by a continuous on-line analysis, it is obvious that making the briquette for analyzing the sample is complex and sensitive to damages. When analyzing mineral slurries, it is usually preferable to remove water from the sample before analyzing the same. Dewatering the sample makes the analyzing result more accurate and improves the sensitivity to measurement, when analyzing the sample by a measuring technique based on laser beams or X-rays or neutron activation, for example. Known methods of dewatering mineral slurries include thickening/clarification or filtering, wherein, because of the nature of these methods, however, coarse material separates out from the fines. When preparing the sample directly from the process for the real-time analysis, however, the sample should be representative with respect to its particle size distribution, and the shape and weight of the particles. Hence, it is not preferable to directly apply thickening or filtering to the preparation of the sample for the on-line analysis in the methods mentioned above.